Makindo Medical Notes

☢️ Radiation exposure can come from natural sources (radon gas, cosmic rays, radioactive minerals) or human-made sources (medical imaging, nuclear power, radiotherapy). While radiation has important medical uses, uncontrolled exposure can cause serious harm to health.

⚡ Types of Radiation

• Ionizing Radiation ⚡
  • X-rays, gamma rays, alpha particles, beta particles, neutrons.
  • High energy → ionises atoms → DNA damage & tissue injury.
• Non-ionizing Radiation 📡
  • UV rays, visible light, infrared, microwaves, radiofrequency.
  • Lower energy → less harmful, but UV can cause skin cancer.

🧬 Biological Effects of Ionizing Radiation

• Cellular Damage 🔬
  • Direct DNA damage or indirect ROS (free radicals).
  • Can lead to mutations, cell death, or malignancy.
• Deterministic Effects (dose-dependent) 📈
  • Severity ↑ with dose.
  • Burns, radiation sickness, organ failure.
  • Examples: skin erythema, alopecia, cataracts, ARS.
• Stochastic Effects (probability-based) 🎲
  • Risk ↑ with dose, severity not dose-related.
  • Cancers (leukaemia, thyroid, lung, solid tumours), genetic mutations.

🚨 Acute Radiation Syndrome (ARS)

• Hematopoietic Syndrome (1–10 Gy) 🩸 → marrow failure → anaemia, infection, bleeding.
• Gastrointestinal Syndrome (10–20 Gy) 🍽️ → nausea, vomiting, diarrhoea, dehydration.
• Cerebrovascular Syndrome (>20 Gy) 🧠 → neurological collapse, coma, death within days.

⏳ Long-term Effects

• Cancers 🎗️ → leukaemia, thyroid, breast, lung, solid tumours (latency years–decades).
• Genetic Effects 👶 → heritable mutations, congenital anomalies.
• Cardiovascular Disease ❤️ → vascular & heart damage, ↑ risk of stroke & MI.
• Chronic Radiation Syndrome 😴 → fatigue, memory loss, immune dysfunction from prolonged low-dose exposure.

🛡️ Protection & Mitigation

• ⏱️ Time: Minimise exposure duration.
• 📏 Distance: Stay as far from source as possible.
• 🧱 Shielding: Use barriers (lead aprons, concrete walls).
• 🧤 PPE: Gloves, masks, protective clothing for handling materials.
• 📊 Monitoring: Dosimeters to track exposure.
• 📑 Regulations: Follow ICRP & NCRP safety standards.

📊 Common Radiation Doses (Examples)

• 🍌 Eating a banana: ~0.1 μSv
• 🦷 Dental X-ray: ~5 μSv
• 🛫 Flight (LA → NYC): ~40 μSv
• 🫁 Chest X-ray: ~0.1 mSv
• 🖥️ Chest CT: ~7 mSv
• 🧍 Whole-body CT: ~10 mSv
• ❤️ Coronary CT Angio: ~12 mSv
• ⚛️ PET/CT: ~25 mSv
• 👷 Radiation worker limit (1 yr): 50 mSv
• 🔥 Chernobyl emergency worker: ~0.25 Sv
• 💥 Hiroshima survivor: ~0.5 Sv
• ☠️ 8 Sv: lethal (50–100% mortality in 7 days, even with treatment)

📌 Summary

Radiation can cause harm ranging from acute radiation syndrome to late cancers & genetic effects. Understanding dose, type, and protective measures is essential for safe use, especially in medical & nuclear settings.

📅 Revisions

• Last updated: 02/08/2018